Semi-conductor components are generally produced in large quantities. To rapidly test large quantities of components, automatic test equipment (generally xe2x80x9ctestersxe2x80x9d) is used. A tester rapidly generates input signals for application to the integrated circuit and can determine whether the appropriate response signals are generated. Because testers are highly automated, they can run through a series of millions of test cases in a few seconds.
To efficiently test integrated circuits, some device is needed to move and quickly connect the device being tested to the tester. To move wafers, a device called a xe2x80x9cprober xe2x80x9dis used. To move packaged parts a device called xe2x80x9ca handlerxe2x80x9d is used. These devices precisely position the component being tested so that it makes electrical contact with outputs of the tester. Probers, handlers, and other devices for positioning a device under test relative to the test head are called xe2x80x9chandling devicesxe2x80x9d.
Semi-conductor test systems are used for testing integrated circuit devices to verify their performance characteristics. For limited volume testing, the integrated circuit device can be placed in a test fixture that is mounted on a device-under-test (DUT) board, or the DUT board can be docked with a semi-conductor wafer prober or package handler for high volume production testing. Conventional testing employs a probe card that is provided with a large number of small tungsten blades or needles that are mechanically and electrically connected to a circuit board and act as test probe contacts. Electrical leads extend from the contacts to the outer edge of the board for connecting the probe card to test circuitry. In use, the blades or needles are moved into engagement with the pads of an integrated circuit. The ends of the test needles or blades must all fall in the same plane in order to assure that each blade or pin makes electrical contact with a pad of the integrated circuit. In order to ensure proper electrical contact, the blades or needles must be adjusted after they have been mounted on the probe card. This adjustment is time consuming and expensive. Even after such adjustment, a loss of adjustment can come about from the pressure of the needles against the chips. As a result, constant maintenance is necessary or the probe cards will not perform their intended function.
A problem arises when the xe2x80x9ctest headxe2x80x9d assembly, currently used on industry testers, docks (comes in contact) with the DUT board assembly. In a wafer test set-up, a test frame is cabled to a movable test head. The movable test head docks with a prober. The prober holds the DUT board assembly and moves product wafers to the probe tips and removes wafers after test. Typical test head assemblies contain electronics and cooling hardware and subsequently are quite heavy (800 to 1200lbs). When the test head assemblies dock with a prober, the hardware which holds the DUT board assembly gets deflected. This deflection causes non-symmetrical distortion of the probe tip plane. The probe mechanism must be adjusted in order to maintain a constant plane between the probe tip plane and the DUT board assembly. In the test head assemblies, once the DUT board assembly is installed into a prober and once a test head has docked, the probe mechanism is very difficult to see, reach and adjust. Because of the time consuming process of adjusting the probe tip plane and the probe mechanism and the difficulty in observing and manipulating the probe mechanism, current systems are inefficient and difficult to use. The non-symmetrical distortion of the probe tip plane and the probe mechanism creates time consuming adjustments. Accordingly, there exists a need for a planarization tool of improved construction.
An exemplary embodiment is a method and apparatus for planarization. The planarization tool has a base which provides the support for the planarization tool. The base has a support hinge mounted on it along with dampening posts and rest posts which support a pivot plate hinged to the support hinge. A pressure assembly is mounted to the pivot plate by retention hardware. The pressure assembly loads a device under test board assembly that is mounted to the pressure assembly with the retention hardware.